1. Field of the Invention
The present invention relates to a detection of a relative address on an optical storage medium, and more particularly, to an apparatus and method of detecting a relative address, for example, relative position information, recorded in a land pre-pit block of an optical storage medium and correcting an error in the relative address.
2. Description of the Related Art
An optical storage medium, such as a DVD-R or DVD-RW, includes a land pre-pit (LPP) formed by embossing a series of microscopic pits, including address information, in a land during a manufacturing of the optical storage medium. An LPP signal is detected as a light beam follows a track of the optical storage medium. A recording apparatus measures the LPP signal using an optical pickup before and after a recording operation.
An optical storage medium includes an LPP block (i.e., a pre-recorded block) composed of 16 LPP sectors (i.e., pre-recorded sectors). The LPP block is referred to as a “pre-recorded data block” or “pre-recorded physical block” according to a signal processing stage.
The pre-recorded data block includes two data portions A and B. The portion A is composed of a 3-byte error correction code (ECC) block address and a 3-byte parity. In other words, the portion A is composed of 6 pre-recorded data sectors. The portion B is composed of a 1-byte ID field, a 6-byte disc information, and a 3-byte parity. In other words, the portion B is composed of 10 pre-recorded data sectors.
The pre-recorded data block is composed of 16 pre-recorded physical sectors including the portion A, the portion B, and relative addresses of 0000b through 1111b. The pre-recorded physical block is formed by adding a pre-recorded sync to the pre-recorded data block.
A relative address included in an LPP sector is 4 bits in length and indicates a position of the LPP sector among 16 LPP sectors (i.e., 1 LPP block). The relative addresses 0000b through 1111b respectively indicate a first LPP sector through a last LPP sector. A relative address number is the same as the lower 4 bits of a physical sector number recorded in a groove. A relative address does not have an ECC or an error detection code (EDC).
Where a relative address in an LPP block is incorrectly detected while information is recorded on or reproduced from an optical storage medium, a decoding error occurs even if other data in the LPP block is correctly detected.
Therefore, an apparatus and method of correcting an error, during a detecting of a relative address that does not have an EDC or ECC, is desired.